Field
This application relates to a conductive ink, particularly to a conductive ink including nickel.
Description of the Related Art
The most common and highest performing conductive inks available on the market are silver inks. The biggest downside of these inks is cost due to silver content (varying from 1 to 2 dollars per gram). Copper inks are also available and are cheaper than silver inks; however, the copper inks themselves and the films printed using the copper inks are prone to oxidation and corrosion.
Nickel (Ni) has inherent metal conductivity, high resistance to oxidation and other types of corrosion, and is magnetic. Based on these properties, Ni inks find applications in many areas including conductive inks, decorative metallic paints, corrosion resistant coatings, antistatic coatings, and in radio frequency and electromagnetic shielding coatings.
Conductive screen printable Ni inks available on the market have a range of sheet resistance between about 5 Ohm/sq/mil and about 300 Ohm/sq/mil, which is relatively high compared to what one would expect from a metal ink. The relatively low conductivity of existing Ni inks might also explain why there are not many suppliers of such materials (e.g., existing suppliers include Creative Materials, Corp., Gwent Electronic Materials, Ltd., Engineered Conductive Materials, LLC, and Epoxies, etc.). There are also existing suppliers producing ink-jet printable nano Ni inks (e.g., Applied Nanotech Holdings, Inc.). Although, nanoinks cured at temperatures above 300° C. are highly conductive (e.g., they can become a thin metal film after curing), they are expensive and not applicable where a thicker coating or lower curing temperatures are needed. They are also more difficult to produce in large quantities due to the nanomaterials.
Therefore, there is a need for Ni ink having improved properties.